AES E-Library

AES E-Library

In this paper, we propose a beam-forming speaker based on digitally direct driven speaker system (digital-SP); the proposed speaker employs multi-bit delta-sigma modulation in addition to a line speaker array with flat-panel-loudspeakers (FPLS) and a delay circuit. The proposed speaker can be realized only by D flip-flops and digital-SP. The sound direction can easily be controlled digitally. All processes can be performed digitally without the use of analog components such as power amplifiers, and a small, light, thin, high-quality beam-forming speaker system can be realized. The prototype is constructed using an FPGA, CMOS drivers, and a line FPLS array. The 20dB attenuation for 20 degree direction is measured.